The researchers used APT oxidation reduction to produce submicron spherical tungsten powder, which has advantages of less pollution, narrow particle size distribution, simple equipment, simple and easy process line. Also, it is easy to control process parameters. And it is suitable for industrial mass production. The obtained tungsten powder is spherical, which is beneficial to the shrinkage and uniformity during calcination process, so as to better control the grain size.
More details, please visit:
http://ammonium-paratungstate.com/index.html
APT Oxidation Reduction Producing Submicron Spherical Tungsten Powder
Step One: Heat ammonium paratungstate (APT) to 800 °C in argon at a slow heating rate and retain for 10 min at 800 °C to obtain violet tungsten oxide (VTO).
Step Two: Reduce VTO obtained in Step One to produce tungsten powder.
Step Three: Oxidize tungsten powder by heating to 500 °C, when temperature reaches 500 °C, keep it warm for 10 min to obtain tungsten trioxide.
Step Four: Reduce tungsten trioxide in hydrogen for the second time, produce tungsten powder.
Step Five: Use tungsten powder obtained in Step Four and repeat the process in Step Three, making a second oxidation to obtain tungsten trioxide.
Step Six: Use tungsten trioxide from Step Five to repeat process in Step Two, making the third reduction and obtain tungsten powder.
